Device for testing hardness



Feb. 12 19241.

R. B. ADAMS DEVICE FOR-TESTING HARDNESS I Filed Dec. 9. 1922 jzverv WM Q MM I Patented Feb. 12,1924.

MASSACHUSETTS.

U IT D STATES PATENT OFFICE.

mn1envs. sums, 01 mirror, M SSACHUSETTS, assronon 'ro s'rown a ween-. wean serum, or nn'w'ron UPPER FALLS, unssacnusnrrs, a conroaa'rron P DEVICE FOR TETING HABDNESSQ Application filed December 9, 1922. Serial No. 6 05,95 7.

To all whm it m concem:

Be it known that I, RALEIGH B. ADAMS, of Newton in the county of Middlesex and State of Massachusetts, have invented a new and useful Device for Testing Hardness,

of which the following is, a specification.

- The principal object of my invention is to provide a portable device for testing hardness. of rubber and 10 covered rolls,

A feature of'my invention is that it is a com act and complete portable entit ready or direct testin wherever desire Another feature is t at it comprises an external substantially flat surface toengage the material to be tested combined with a relatively hard nose movable with relation to said surface to enter said :material and through connecting mechanism indicate the- 0 hardness of the material.

Fi re 4 is apartial sectlonon the line 4-4 of Figure 3; and

Figure 5 is a fragmentary elevation of the casing.

Casing A is cylindrical, being open at the front and havin back wall a, the latter bei as ing provided wit openings (not shown) for the shanks of attaching screws. Annular shoulders a and a are rovided for cooperation with the base as ascribed below. Integral with the casing is neck A internally 40 threaded to engage the external threading of hollow bearing member A3 and also to engage. the external threading of cap a. At one external portion of the bottom of the casing I provide a fiat metal shelf or abutment A perforated at A, this perfora tion extending inwardly through the wall of the casing, said perforation and them'emher A providing bearings for steel spindle A, which has a hemispherical hardened nose or point A to rats the material to be Jaws A. an A are clamped to the spindle by screw 01' and form a lower abutment for spring A which iscoiled around the spindle and .at its upper end' abuts the particularly rubber.

against the bottom of member A and tends to force jaws'A and Av against fiat portion a of the casing. Casing A has an integral projection A to which is attached guide member A by means of screw A, a portion of member A being spaced from project-ion A to form a guide way forjaw A, the latter being provided with a shoulder A to engage the indicator operatingmechanism as more fully described below.

Base Bv is cylindricaland fits within the casing being held thereto by screws whose shanks pass through the opening above referred to in the back wall a and whose threading engage the threaded holes 6 and b in the base. The base mayv have a knurled member B crimped to hold in place the glass B and dial B lhe base. is provided with internall projecting tubular guides B and B an aligned openings B and B, this. construction being to permit movement of, and to guide rack bar B which' is held normally in its lower position 3 'by'spring b connected at one end to the base and at the other. end to pin bf fixed to the rack bar which may be flat intermediate or its ends. Guide B has a slot 7) to permit, and limit, movement of pin 6 fixed to the rack bar, said pin normally engagin the top of shoulder A, sothat when said s oulder is raised the rack bar will be raised and rotate. pinion 6, upon 'whose shaft is fixed gear b, the latter operating pinion 6, upon whose shaft is fixed gear 6, the latter operating pinion 6, upon whose shaft is fixed ointer B". I also provide gear 6. whic engages pinion 6 and which, under the influence of spring b, tends to return the pointer to normal position.

When my device is applied to the material to be tested, as, for example, to the surface of a rubber roll the nose A is pressed into the material until the latter is ust tan nt to the fiat surfaceA the move-f ment o said nose inwardly of the casing beingresisted by the compression spring A. The force exerted by said spring is predetermined and the size of said nose is predetermined and the relation of said force and size are preferabl such that when sa d tangency occurs to readin of the indicater .dial will show the num er of 50ths of I amilllirneter that a steel ball '5 of an inch in diameter would penetrate the rubber it it were forced into the rubber by a force equal to the weight of one kilogram.

The compression of spring A may be readily adjusted by adjustment of the jaws A and A and I have atv all times a portable and extremely accurate instrument'for measuring the hardnes's of rubber or other material.

An important advantage of my instrument is that it can be made in quantities so that all instruments will register alike for a given hardness and the hardness expressed by the dial. readin is comparable. with a reco nized standar The standard commo used in the rubber roll industry is base on the number of hundredths of a millimeter a steel ball in diameter will penetrate under the force e ual to the weight of one kilogram. The bar ness of any piece of rubber tested by my instrument will therefore be one-half the reading which would be found by the standard plastometer.

It will be clearthat my device is a convenient portable shop instrument by means of which a roll can'be tested in the machine in which it is operating and my instrument is therefore a valuable scientific tool.

What IQaim is:

1. A device of the character described comprising a casing having an abutment to engage the material to be tested; a spindle mounted to move inwardly with reference to said casing when pressed by the material, said spindle having an end to engagethe material;a spring tending to resist the inward movement of the spindle, the size of said end and the resistance of said spring havin a predetermined relation when the material engages said abutment; means to adjust the compression of said sprin and means operatively connected with sai spindiel to indicate the hardness of the materia 2. A device for testing the hardness of rubber rolls comprising a casing having a fiat, external, abutment surface to engage the material to be tested; a spindle having a substantially hemispherical end normally projecting beyond said surface, said spindle being mounted to move inwardly with reference to said casing when said end is pressed by the material; a compression spring tending to resist the inward movement of the spindle, the size and shape of said end and t a resistance of said spring having a predetermined relation when the material engages said abutment; means to adjust the compression of said spring; and means operativel connected with said spindle to indicate t e hardness of the material.

RALEIGH B. ADAMS. 

